scholarly journals Hap2-Ino80 facilitated transcription promotes de novo establishment of CENP-A chromatin

2019 ◽  
Author(s):  
Puneet P. Singh ◽  
Manu Shukla ◽  
Sharon A. White ◽  
Pin Tong ◽  
Tatsiana Auchynnikava ◽  
...  
Keyword(s):  
Fission Yeast ◽  
De Novo ◽  
Histone H3 ◽  
Chromatin Assembly ◽  
Centromere Function ◽  
Kinetochore Assembly ◽  
Auxiliary Subunit ◽  
Evolutionarily Conserved ◽  
Histone H3 Variant ◽  
Chromatin Integrity

SUMMARYCentromeres are maintained epigenetically by the presence of CENP-A, an evolutionarily-conserved histone H3 variant, which directs kinetochore assembly and hence, centromere function. To identify factors that promote assembly of CENP-A chromatin, we affinity selected solubilised fission yeast CENP-ACnp1 chromatin. All subunits of the Ino80 complex were enriched, including the auxiliary subunit Hap2. In addition to a role in maintenance of CENP-ACnp1 chromatin integrity at endogenous centromeres, Hap2 is required for de novo assembly of CENP-ACnp1 chromatin on naïve centromere DNA and promotes H3 turnover on centromere regions and other loci prone to CENP-ACnp1 deposition. Prior to CENP-ACnp1 chromatin assembly, Hap2 facilitates transcription from centromere DNA. These analyses suggest that Hap2-Ino80 destabilises H3 nucleosomes on centromere DNA through transcription-coupled histone H3 turnover, driving the replacement of resident H3 nucleosomes with CENP-ACnp1 nucleosomes. These inherent properties define centromere DNA by directing a program that mediates CENP-ACnp1 assembly on appropriate sequences.

scholarly journals The role of heterochromatin in centromere function

2005 ◽  
Vol 360 (1455) ◽  
pp. 569-579 ◽  
Author(s):  
Alison L Pidoux ◽  
Robin C Allshire
Keyword(s):  
Fission Yeast ◽  
Histone H3 ◽  
Centromeric Heterochromatin ◽  
Chromatin Domain ◽  
Heterochromatin Protein 1 ◽  
Heterochromatin Protein ◽  
Centromere Function ◽  
Kinetochore Assembly ◽  
Histone H3 Variant

Chromatin at centromeres is distinct from the chromatin in which the remainder of the genome is assembled. Two features consistently distinguish centromeres: the presence of the histone H3 variant CENP-A and, in most organisms, the presence of heterochromatin. In fission yeast, domains of silent ‘heterochromatin’ flank the CENP-A chromatin domain that forms a platform upon which the kinetochore is assembled. Thus, fission yeast centromeres resemble their metazoan counterparts where the kinetochore is embedded in centromeric heterochromatin. The centromeric outer repeat chromatin is underacetylated on histones H3 and H4, and methylated on lysine 9 of histone H3, which provides a binding site for the chromodomain protein Swi6 (orthologue of Heterochromatin Protein 1, HP1). The remarkable demonstration that the assembly of repressive heterochromatin is dependent on the RNA interference machinery provokes many questions about the mechanisms of this process that may be tractable in fission yeast. Heterochromatin ensures that a high density of cohesin is recruited to centromeric regions, but it could have additional roles in centromere architecture and the prevention of merotely, and it might also act as a trigger for kinetochore assembly. In addition, we discuss an epigenetic model for ensuring that CENP-A is targeted and replenished at the kinetochore domain.

scholarly journals CENP-A exceeds microtubule attachment sites in centromere clusters of both budding and fission yeast

2011 ◽  
Vol 195 (4) ◽  
pp. 563-572 ◽  
Author(s):  
Valerie C. Coffman ◽  
Pengcheng Wu ◽  
Mark R. Parthun ◽  
Jian-Qiu Wu
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Schizosaccharomyces Pombe ◽  
Fission Yeast ◽  
Budding Yeast ◽  
Histone H3 ◽  
Kinetochore Assembly ◽  
Microtubule Attachment ◽  
Attachment Sites ◽  
Histone H3 Variant ◽  
Architectural Models

The stoichiometries of kinetochores and their constituent proteins in yeast and vertebrate cells were determined using the histone H3 variant CENP-A, known as Cse4 in budding yeast, as a counting standard. One Cse4-containing nucleosome exists in the centromere (CEN) of each chromosome, so it has been assumed that each anaphase CEN/kinetochore cluster contains 32 Cse4 molecules. We report that anaphase CEN clusters instead contained approximately fourfold more Cse4 in Saccharomyces cerevisiae and ∼40-fold more CENP-A (Cnp1) in Schizosaccharomyces pombe than predicted. These results suggest that the number of CENP-A molecules exceeds the number of kinetochore-microtubule (MT) attachment sites on each chromosome and that CENP-A is not the sole determinant of kinetochore assembly sites in either yeast. In addition, we show that fission yeast has enough Dam1–DASH complex for ring formation around attached MTs. The results of this study suggest the need for significant revision of existing CEN/kinetochore architectural models.

scholarly journals Trans-generational inheritance of centromere identity requires the CENP-A N-terminal tail in the C. elegans maternal germ line

2020 ◽  
Author(s):  
Reinier F. Prosée ◽  
Joanna M. Wenda ◽  
Caroline Gabus ◽  
Kamila Delaney ◽  
Francoise Schwager ◽  
...  
Keyword(s):  
De Novo ◽  
Germ Line ◽  
Protein A ◽  
Histone H3 ◽  
Centromeric Chromatin ◽  
C Elegans ◽  
Centromere Function ◽  
Centromere Protein A ◽  
Histone H3 Variant ◽  
Meiosis I

AbstractCentromere protein A (CENP-A) is a histone H3 variant that defines centromeric chromatin and is essential for centromere function. In most eukaryotes CENP-A-containing chromatin is epigenetically maintained, and centromere identity is inherited from one cell cycle to the next. In the germ line of the holocentric nematode Caenorhabditis elegans, this inheritance cycle is disrupted. CENP-A is removed at the mitosis-to-meiosis transition and is established de novo on chromatin during diplotene of meiosis I. Here we show that the N-terminal tail of CENP-A is required for the de novo establishment of centromeres, but dispensable for centromere maintenance during embryogenesis. Worms homozygous for a CENP-A tail deletion maintain a functional centromere during development, but give rise to inviable offspring because they fail to re-establish centromeres in the maternal germ line. We identify the N-terminal tail of CENP-A as a critical domain for the interaction with the conserved kinetochore protein KNL-2, and argue that this interaction plays an important role in setting centromere identity in the germ line. We conclude that centromere establishment and maintenance are functionally distinct in C. elegans.

scholarly journals The N-terminal Tail of C. elegans CENP-A Interacts with KNL-2 and is Essential for Centromeric Chromatin Assembly

2020 ◽  
Author(s):  
Christian de Groot ◽  
Jack Houston ◽  
Bethany Davis ◽  
Adina Gerson-Gurwitz ◽  
Joost Monen ◽  
...  
Keyword(s):  
Histone H3 ◽  
Direct Interaction ◽  
Chromatin Assembly ◽  
Nucleosome Assembly ◽  
Centromeric Chromatin ◽  
C Elegans ◽  
Histone Fold ◽  
Kinetochore Assembly ◽  
Histone H3 Variant ◽  
Evolutionary Variation

ABSTRACTCentromeres are epigenetically defined by the presence of the centromere-specific histone H3 variant CENP-A. A specialized loading machinery, including the histone chaperone HJURP/Scm3, participates in CENP-A nucleosome assembly. However, Scm3/HJURP is missing from multiple lineages, including nematodes, which rely on a CENP-A-dependent centromere. Here, we show that the extended N-terminal tail of C. elegans CENP-A contains a predicted structured region that is essential for centromeric chromatin assembly. Removal of this region of the CENP-A N-Tail prevents loading, resulting in failure of kinetochore assembly and defective chromosome condensation. By contrast, the N-Tail mutant CENP-A localizes normally in the presence of endogenous CENP-A. The portion of the N-Tail containing the predicted structured region binds to KNL-2, a conserved SANTA and Myb domain-containing protein (referred to as M18BP1 in vertebrates), that is specifically involved in CENP-A chromatin assembly. This direct interaction is conserved in the related nematode C. briggsae, despite divergence of the N-Tail and KNL-2 primary sequences. Thus, the extended N-Tail of CENP-A is essential for CENP-A chromatin assembly in C. elegans and partially substitutes for the function of Scm3/HJURP, in that it mediates an interaction of the specialized histone fold of CENP-A with KNL-2. These results highlight an evolutionary variation on centromeric chromatin assembly in the absence of a dedicated CENP-A-specific chaperone/targeting factor of the Scm3/HJURP family.

scholarly journals Swr1 mediated H2A.ZPht1 incorporation designates centromere DNA for de novo CENP-ACnp1 assembly

2017 ◽  
Author(s):  
Raghavendran Kulasegaran-Shylini ◽  
Lakxmi Subramanian ◽  
Alastair R. W. Kerr ◽  
Christos Spanos ◽  
Juri Rappsilber ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Fission Yeast ◽  
De Novo ◽  
Histone H3 ◽  
S Phase ◽  
Chromatin Integrity

SUMMARYThe underlying hallmark of centromeres is the presence of specialized nucleosomes in which histone H3 is replaced by CENP-A. The events that mediate the installation of CENP-A in place of H3 remain poorly characterized. H2A.Z is linked to transcriptional competence and associates with mammalian centromeres. We find that H2A.ZPht1 and the Swr1 complex are enriched in fission yeast CENP-ACnp1 chromatin. Our analysis shows that Swr1, Msc1 and H2A.ZPht1 are required to maintain CENP-ACnp1 chromatin integrity. Cell cycle analyses demonstrate that H2A.ZPht1 is deposited in S phase, coincident with the deposition of placeholder H3, and prior to CENP-ACnp1 replenishment in G2. Establishment assays reveal that H2A.ZPht1 and Swr1 are required for de novo assembly of CENP-ACnp1 onto naïve centromere DNA. We propose that features akin to promoters within centromere DNA program the incorporation of H2A.ZPht1 via Swr1, and mediate the replacement of resident H3 nucleosomes with CENP-A nucleosomes thereby defining centromeres.

scholarly journals Centromeric chromatin gets loaded

2007 ◽  
Vol 176 (6) ◽  
pp. 735-736 ◽  
Author(s):  
Christopher W. Carroll ◽  
Aaron F. Straight
Keyword(s):  
Chromosome Segregation ◽  
Molecular Mechanisms ◽  
Protein A ◽  
Histone H3 ◽  
Chromatin Assembly ◽  
Centromeric Chromatin ◽  
Kinetochore Assembly ◽  
Centromere Protein A ◽  
Specific Loading ◽  
Histone H3 Variant

Centromeric nucleosomes contain a histone H3 variant called centromere protein A (CENP-A) that is required for kinetochore assembly and chromosome segregation. Two new studies, Jansen et al. (see p. 795 of this issue) and Maddox et al. (see p. 757 of this issue), address when CENP-A is deposited at centromeres during the cell division cycle and identify an evolutionally conserved protein required for CENP-A deposition. Together, these studies advance our understanding of centromeric chromatin assembly and provide a framework for investigating the molecular mechanisms that underlie the centromere-specific loading of CENP-A.

scholarly journals Transgenerational inheritance of centromere identity requires the CENP-A N-terminal tail in the C. elegans maternal germ line

PLoS Biology ◽  
2021 ◽  
Vol 19 (7) ◽  
pp. e3000968
Author(s):  
Reinier F. Prosée ◽  
Joanna M. Wenda ◽  
Isa Özdemir ◽  
Caroline Gabus ◽  
Kamila Delaney ◽  
...  
Keyword(s):  
De Novo ◽  
Germ Line ◽  
Protein A ◽  
Histone H3 ◽  
Transgenerational Inheritance ◽  
Centromeric Chromatin ◽  
C Elegans ◽  
Centromere Function ◽  
Centromere Protein A ◽  
Histone H3 Variant

Centromere protein A (CENP-A) is a histone H3 variant that defines centromeric chromatin and is essential for centromere function. In most eukaryotes, CENP-A-containing chromatin is epigenetically maintained, and centromere identity is inherited from one cell cycle to the next. In the germ line of the holocentric nematode Caenorhabditis elegans, this inheritance cycle is disrupted. CENP-A is removed at the mitosis-to-meiosis transition and is reestablished on chromatin during diplotene of meiosis I. Here, we show that the N-terminal tail of CENP-A is required for the de novo establishment of centromeres, but then its presence becomes dispensable for centromere maintenance during development. Worms homozygous for a CENP-A tail deletion maintain functional centromeres during development but give rise to inviable offspring because they fail to reestablish centromeres in the maternal germ line. We identify the N-terminal tail of CENP-A as a critical domain for the interaction with the conserved kinetochore protein KNL-2 and argue that this interaction plays an important role in setting centromere identity in the germ line. We conclude that centromere establishment and maintenance are functionally distinct in C. elegans.

scholarly journals De Novo Kinetochore Assembly Requires the Centromeric Histone H3 Variant

2005 ◽  
Vol 16 (12) ◽  
pp. 5649-5660 ◽  
Author(s):  
Kimberly A. Collins ◽  
Andrea R. Castillo ◽  
Sean Y. Tatsutani ◽  
Sue Biggins
Keyword(s):  
Chromosome Segregation ◽  
Mitotic Spindle ◽  
De Novo ◽  
Histone H3 ◽  
Centromeric Chromatin ◽  
Centromeric Dna ◽  
Kinetochore Assembly ◽  
Histone H3 Variant ◽  
Chromosome Attachment ◽  
Dna Specificity

Kinetochores mediate chromosome attachment to the mitotic spindle to ensure accurate chromosome segregation. Budding yeast is an excellent organism for kinetochore assembly studies because it has a simple defined centromere sequence responsible for the localization of >65 proteins. In addition, yeast is the only organism where a conditional centromere is available to allow studies of de novo kinetochore assembly. Using a conditional centromere, we found that yeast kinetochore assembly is not temporally restricted and can occur in both G1 phase and prometaphase. We performed the first investigation of kinetochore assembly in the absence of the centromeric histone H3 variant Cse4 and found that all proteins tested depend on Cse4 to localize. Consistent with this observation, Cse4-depleted cells had severe chromosome segregation defects. We therefore propose that yeast kinetochore assembly requires both centromeric DNA specificity and centromeric chromatin.

scholarly journals The N-terminal Tail of C. elegans CENP-A Interacts with KNL-2 and is Essential for Centromeric Chromatin Assembly

2021 ◽  
pp. mbc.E20-12-0798
Author(s):  
Christian de Groot ◽  
Jack Houston ◽  
Bethany Davis ◽  
Adina Gerson-Gurwitz ◽  
Joost Monen ◽  
...  
Keyword(s):  
Histone H3 ◽  
Direct Interaction ◽  
Chromosome Condensation ◽  
Chromatin Assembly ◽  
Nucleosome Assembly ◽  
Centromeric Chromatin ◽  
C Elegans ◽  
Kinetochore Assembly ◽  
Histone H3 Variant ◽  
Evolutionary Variation

Centromeres are epigenetically defined by the centromere-specific histone H3 variant CENP-A. Specialized loading machinery, including the histone chaperone HJURP/Scm3, participates in CENP-A nucleosome assembly. However, Scm3/HJURP is missing from multiple lineages, including nematodes, with CENP-A-dependent centromeres. Here, we show that the extended N-terminal tail of C. elegans CENP-A contains a predicted structured region that is essential for centromeric chromatin assembly; removal of this region prevents CENP-A loading, resulting in failure of kinetochore assembly and defective chromosome condensation. By contrast, the N-Tail mutant CENP-A localizes normally in the presence of endogenous CENP-A. The portion of the N-Tail containing the predicted structured region binds to KNL-2, a conserved SANTA and Myb domain-containing protein (referred to as M18BP1 in vertebrates) specifically involved in CENP-A chromatin assembly. This direct interaction is conserved in the related nematode C. briggsae, despite divergence of the N-Tail and KNL-2 primary sequences. Thus, the extended N-Tail of CENP-A is essential for CENP-A chromatin assembly in C. elegans and partially substitutes for the function of Scm3/HJURP, in that it mediates a direct interaction between CENP-A and KNL-2. These results highlight an evolutionary variation on centromeric chromatin assembly in the absence of a dedicated CENP-A-specific chaperone/targeting factor of the Scm3/HJURP family.

scholarly journals Centromeric DNA destabilizes H3 nucleosomes to promote CENP-A deposition during the cell cycle

2017 ◽  
Author(s):  
Manu Shukla ◽  
Tong Pin ◽  
Sharon A. White ◽  
Puneet P. Singh ◽  
Angus M. Reid ◽  
...  
Keyword(s):  
Feedback Loop ◽  
Chromosomal Location ◽  
Nucleosome Occupancy ◽  
Histone H3 ◽  
S Phase ◽  
Intrinsic Properties ◽  
Centromeric Dna ◽  
Kinetochore Assembly ◽  
Histone H3 Variant ◽  
Specific Sequences

SummaryActive centromeres are defined by the presence of nucleosomes containing CENP-A, a histone H3 variant, which alone is sufficient to direct kinetochore assembly. Once assembled at a location CENP-A chromatin and kinetochores are maintained at that location though a positive feedback loop where kinetochore proteins recruited by CENP-A itself promote deposition of new CENP-A following replication. Although CENP-A chromatin itself is a heritable entity, it is normally associated with specific sequences. Intrinsic properties of centromeric DNA may favour the assembly of CENP-A rather than H3 nucleosomes. Here we investigate histone dynamics on centromeric DNA. We show that during S-phase histone H3 is deposited as a placeholder at fission yeast centromeres and is subsequently evicted in G2 when we detect deposition of the majority of new CENP-ACnp1. We also find that centromeric DNA has an innate property of driving high rates of turnover of H3 containing nucleosomes resulting in low nucleosome occupancy. When placed at an ectopic chromosomal location in the absence of any CENP-ACnp1 assembly, centromeric DNA retains its ability to impose S-phase deposition and G2 eviction of H3, suggesting that features within this DNA program H3 dynamics. As RNAPII occupancy on this centromere DNA coincides with H3 eviction in G2, we propose a model in which RNAPII-coupled chromatin remodelling promotes replacement of H3 with CENP-ACnp1 nucleosomes.

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